Answer:
The 95% confidence interval estimate of the population mean life of the new light-bulb is (469.21 hours, 510.79 hours).
This confidence level means that we are 95% sure that the true population mean life of the new light bulb is in this interval.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now we find M as such:
In which 
is the standard deviation of the population and n is the length of the sample. So:
The lower end of the interval is the mean subtracted by M. So it is 490 - 20.79 = 469.21 hours.
The upper end of the interval is the mean added to M. So it is 490 + 20.79 = 510.79 hours.
The 95% confidence interval estimate of the population mean life of the new light-bulb is (469.21 hours, 510.79 hours).
This confidence level means that we are 95% sure that the true population mean life of the new light bulb is in this interval.
I believe this should be it.
Answer:
15.01
Step-by-step explanation:
Tangent=Opposite/adjacent
Tan(65)=?/7
Tangent of 65 x 7=
15.01
Answer:
Paul purchased 23 pieces of pepperoni pizza
Step-by-step explanation:
Let pepperoni pizza pieces = x
and plain pizza pieces = y
So, the equations will be:
AS pepperoni pizza piece is sold for $1.15 and plain pizza is sold for $0.90 and Paul paid $39.05
1.15 x + 0.90 y = 39.05 eq(1)
Paul bought total 37 pieces of pizza so,
x + y = 37 eq(2)
Solving eq(1) and (2) we can find the pieces of pepperoni pizza bought by Paul.
Multiplying equation (2) with 1.15 and subtracting eq(1) and eq(2)
1.15 x + 0.90 y = 39.05
1.15 x + 1.15 y = 42.55
- - -
__________________
0 x - 0.25 y = -3.5
y = -3.5/-0.25
y = 14
Putting value of y in equation(2)
x+y = 37
x + 14 = 37
x = 37 - 14
x = 23
So, Paul purchased 23 pieces of pepperoni pizza as x represents pepperoni pizza pieces.
32.697 rounded to the nearest tenth is 32.700
32.697 rounded to the nearest hundred is 32.700
32.697 rounded to the nearest ones is 32.698
